Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/04—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/00064—Constructional details of the endoscope body
  • A61B1/00071—Insertion part of the endoscope body
  • A61B1/0008—Insertion part of the endoscope body characterised by distal tip features
  • A61B1/00096—Optical elements
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/00163—Optical arrangements
  • A61B1/00188—Optical arrangements with focusing or zooming features
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/04—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
  • A61B1/05—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances characterised by the image sensor, e.g. camera, being in the distal end portion
  • A61B1/051—Details of CCD assembly
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
  • A61B1/04—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances
  • A61B1/055—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor combined with photographic or television appliances having rod-lens arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/50—Constructional details
  • H04N23/55—Optical parts specially adapted for electronic image sensors; Mounting thereof
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/50—Constructional details
  • H04N23/555—Constructional details for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/60—Control of cameras or camera modules
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/60—Control of cameras or camera modules
  • H04N23/66—Remote control of cameras or camera parts, e.g. by remote control devices
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B5/00—Measuring for diagnostic purposes; Identification of persons
  • A61B5/06—Devices, other than using radiation, for detecting or locating foreign bodies ; determining position of probes within or on the body of the patient
  • A61B5/061—Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body
  • A61B5/062—Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body using magnetic field

Definitions

• the present invention relates to endoscopes and, in particular, it concerns a miniature imaging sensor for use with particularly small diameter endoscopes. It is known to employ endoscopes with imaging sensors to obtain images of body cavities including, but not limited to, the lungs, the stomach, the colon, and the abdomen. Endoscopes for imaging cavities within the lungs are typically referred to as “bronchoscopes”, and those for imaging within the colon are typically referred to as “colonoscopes”. All such devices with imaging capabilities for examining the inside of body cavities are referred to herein generically as “endoscopes”. Until recently, flexible endoscopes employed optical fibers to deliver the image from the distal endoscope tip to its proximal end.
• the video camera has an automated gain control (AGC) that controls the exposure duration in order to avoid saturation.
• AGC automated gain control
• the AGC can be implemented internally, occupying some physical area, or alternatively the AG can be controlled from the outside via command lines.
• the control signals need to be fed into the image sensor via dedicated lines, in addition to other lines that are required for power and video out. Therefore, the minimum number of lines required is: at least two lines for power, two lines for video output and at least one control line, giving a total of no less than 5 lines. Where active illumination is performed by light emitting elements associated with the endoscope tip, this requires an additional two lines.
• An endoscope includes its own light source to illuminate a scene viewed from its tip.
• the light typically radiates in spherical waves in which the flux density (the power per unit area) drops as the area of the sphere increases.
• the intensity of the light illuminates the objects as a function of the inverse of the square of the distance between the source and the objects.
• Imaging small intrabody cavities such as small bronchial tubes requires a large dynamic sensing range because of the big difference in distances between the adjacent tissue and the relatively far distance seen at the center of this tube.
• LEDs LEDs
• the differing geometrical positions of the light sources for the different colors often causes color imbalance between different parts of the image.
• a further problem in very miniature systems is the proximity of the light source to the image detector array which may lead to light leakage between the lens arrangement and the image sensor array.
• an endoscope with a miniature imaging arrangement.
• an endoscope comprising: (a) an elongated flexible body having a distal tip portion; and (b) an imaging arrangement associated with the distal tip portion, the imaging arrangement including: (i) an image sensor chip including a two-dimensional array of light-sensitive pixels; and (ii) a lens arrangement deployed for focusing light from a field of view onto the image sensor chip so as to generate an image of a scene viewed from the distal tip portion, wherein the lens arrangement is directly affixed to the image sensor chip by a quantity of transparent adhesive.
• the lens arrangement includes a cylindrical graded-index lens.
• the lens arrangement includes a compound lens assembly.
• the lens arrangement has a field of view of at least about 60°, and more preferably at least about 90°.
• an area of the two- dimensional array of light-sensitive pixels is no more than half a square millimeter.
• the imaging arrangement has a diameter of no more than 2 millimeters.
• At least one light source for illuminating the scene viewed from the distal tip portion; and (b) an optically dispersive medium distally overlying the light source such that the optically dispersive medium is effective to disperse illumination from the light source, thereby illuminating the scene viewed from the distal tip portion, without obscuring light reflected from the scene from reaching the lens arrangement.
• the lens arrangement extends distally beyond the at least one light source, and wherein the optically dispersive medium surrounds the lens arrangement without overlying the lens arrangement.
• the imaging arrangement further includes a substantially opaque medium deployed at least between the light source and the two-dimensional array of light-sensitive pixels without obscuring propagation of illumination from the light source towards the scene.
• the imaging arrangement further includes a substantially transparent medium overlying both the optically dispersive medium and the lens arrangement.
• the at least one light source is implemented as a plurality of light sources of different colors.
• the image sensor chip is rectangular, and wherein the plurality of light sources are deployed along no more than two edges of the rectangular chip, the two-dimensional array of light-sensitive pixels being located proximal to a corner of the image sensor chip furthest from the two edges of the rectangular chip.
• the at least one light source and the image sensor chip are deployed on a common circuit board.
• the circuit board fits within a circular cross-section of diameter 2 millimeters.
• a plurality of wires passing along the elongated flexible body for connection to the image sensor chip and the at least one light source, the wires being connected to contact regions of the circuit board on a proximal side of the circuit board.
• the image sensor chip is connected to exactly four of the plurality of wires.
• an endoscope comprising: (a) an elongated flexible body having a distal tip portion; and (b) an imaging system associated with the elongated flexible body, the imaging system including: (i) an image sensor chip including a two-dimensional array of light-sensitive pixels, the image sensor chip being associated with the distal tip portion; (ii) a controller associated with a proximal part of the elongated flexible body, the controller being electrically associated with the image sensor chip via no more than two communication wires extending along the elongated flexible body, wherein the image sensor chip is configured to be responsive to a timing signal generated by the controller to perform a read cycle of the two-dimensional array of light-sensitive pixels in a rolling-shutter mode and to
• the timing signal is a frame request signal
• the image sensor chip is configured to wait after transmitting the single frame of image data until receiving a subsequent frame request signal from the controller.
• the controller is configured to actuate the image sensor chip to generate pairs of similar frames with different exposure durations, the controller being further configured to co-process the pairs of similar frames to derive an enhanced frame having a dynamic range greater than each of the pair of similar frames.
• an illumination system deployed for illuminating a scene viewed from the distal tip portion, the illumination system being configured for selectively illuminating the scene with each of three different colors of visible light, wherein the illumination system is controlled by the controller such that the controller derives an enhanced frame from a pair of similar frames with different exposure durations sampled for each of the three different colors, the controller being further configured to combine the enhanced frames to generate a color image.
• an illumination system including at least one light emitting diode associated with the distal tip portion, the light emitting diode and the image sensor chip being mounted on a common circuit board.
• FIG. 1 is a schematic view of an endoscope, constructed and operative according to the teachings of the present invention
• FIG. 2 is an enlarged schematic isometric view of a distal tip portion of the endoscope of Figure 1 with an outer cover removed to reveal an imaging arrangement, constructed and operative according to the teachings of the present invention
• FIG. 3 is a further enlarged schematic isometric view of the imaging arrangement of Figure 2;
• FIG. 4 is a partially exploded isometric view of the imaging arrangement of Figure 2;
• FIG. 5 is a schematic cross-sectional view taken through the imaging arrangement of Figure 2 illustrating a layered structure of encapsulation of the imaging arrangement according to a further feature of the present invention
• FIG. 6A is a schematic isometric view of an apparatus for use in assembly of the imaging arrangement of Figure 2, the apparatus being shown during a chip alignment step;
• FIG. 6B is an enlarged view of a region of Figure 6 A designated "B";
• FIG. 6C is a schematic isometric view of the apparatus of Figure 6A shown during a lens attachment step
• FIG. 7 is a graphic representation of a relation between pixel output signal and scene brightness for two different durations of exposure, labeled "Ti" and "T 2 ";
• FIG. 8 is a graphic representation of a relation between pixel output signal and scene brightness derived from a pair of exposures of two different durations of exposure as illustrated in Figure 7;
• FIG. 9 is a schematic representation of the layout of a CMOS imaging sensor chip from the imaging arrangement of Figure 2;
• FIG. 10 is a functional representation of the operation of a CMOS image sensor pixel element from the chip of Figure 9;
• FIG. 11 is a schematic representation of a first communication arrangement for bidirectional communication with the imaging sensor arrangement of Figure 2 according to the teachings of the present invention.
• FIG. 12 is a schematic representation of a second communication arrangement for bidirectional communication with the imaging sensor arrangement of Figure 2 according to the teachings of the present invention.
• the present invention is an endoscope with a miniature imaging arrangement.
• Figure 1 shows a general view of an endoscope, generally designated 10, constructed and operative according to the teachings of the present invention.
• the endoscope has an elongated flexible body 12 with a distal tip portion 14.
• an imaging arrangement 16 is associated with distal tip portion 14.
• Imaging arrangement 16 includes an image sensor chip 18 including a two-dimensional array 20 of light-sensitive pixels, and a lens arrangement 22 deployed for focusing light from a field of view onto image sensor chip 18 so as to generate an image of a scene viewed from the distal tip portion.
• elongated flexible body 12 in general, and imaging arrangement 16 in particular is a small caliber device, preferably of outer diameter no more than 3 millimeters, and most preferably of outer diameter no more than about 2 millimeters.
• the endoscope may be inserted via a working lumen of a conventional bronchoscope and advanced into bronchial airways beyond the reach of the conventional bronchoscope where conventional procedures would require working "blind".
• the miniaturization of the imaging arrangement of an endoscope to such small dimensions poses a number of significant problems of implementation.
• the present invention relates primarily to effective solutions for a number of such problems.
• one issue plaguing such miniature implementations of an imaging sensor is how to achieve and maintain correct alignment of lens arrangement 22 with sensor array 20 where both the lens arrangement and the sensor chip have dimensions of the order of a millimeter or less.
• this issue is addressed by directly affixing lens arrangement 22 to image sensor chip 18 by a quantity of transparent adhesive 26 ( Figure 5, shown with slight excess at the sides of the lens).
• an apparatus Figures 6A-6C for facilitating affixing of lens arrangement 22 to image sensor chip 18 in correct alignment with array 20.
• Endoscope 10 includes at least one source of illumination, such as light emitting diodes ("LEDs") 24 «, 24b and 24c. Due to the proximity of the light sources to the sensor array, light may leak around the base of lens arrangement 22, thereby degrading image quality. Furthermore, particularly where separate colored light sources are deployed asymmetrically relative to the lens arrangement, illumination tends to be non-uniform across the viewed scene and dissimilar between the different colors, leading to color imbalance in the output image.
• LEDs light emitting diodes
• the issue of light leakage is addressed as illustrated in Figure 5 by deploying a substantially opaque medium 28 between the light sources 24 «, 246 and 24c and the two-dimensional array 20 of light-sensitive pixels without obscuring propagation of illumination from the light sources 24 «, 24b and 24c towards the scene to be viewed.
• the problem of non-uniform light distribution is addressed, also as illustrated in Figure 5, by deploying an optically dispersive medium 30 distally overlying light sources 24a, 24b and 24c such that medium 30 is effective to disperse illumination from the light source, thereby illuminating the scene viewed from the distal tip portion, without obscuring light reflected from the scene from reaching lens arrangement 22.
• a further issue problematic for the miniaturization of endoscope 10 is the number of connection wires which need to be attached to imaging arrangement 16.
• the number of connections to image sensor chip 18 is reduced to a total of four: two power connections and two communication connections.
• the present invention provides both a system and a method for operating an image sensor system in which two communication connections are used bi-directionally for both a frame request to the imaging arrangement and for outputting data from the imaging arrangement.
• light and illumination are used herein to refer generically to all parts of the electromagnetic spectrum which can be detected by low-cost silicon- based image sensors, such as CMOS sensors. This includes all of the range of wavelengths from near-ultraviolet through to near-infrared (wavelengths of between 0.25 microns and 1.1 microns). Most preferably, visible light in the range of wavelengths from about 0.4 microns to about 0.75 microns is used. The light may be monochromatic, or may contain a number of different colors simultaneously or alternately. Broad spectrum white light may also be used. Certain particularly preferred options for illumination will be discussed below.
• the term "light source” is used herein to refer to any component which releases light from imaging arrangement 16 towards the scene to be viewed.
• the source may either generate light, as in the case of a LED, or may convey light from a remote location, as in the case of an optic fiber conveying light from a source associated with a proximal part of the endoscope body.
• the scene viewed by imaging arrangement 16 may be any scene visible from the distal tip portion 14 of the endoscope.
• the invention is implemented as a forward-looking imaging arrangement where the optical axis of lens arrangement 22 is roughly parallel to a central axis of distal tip portion 14. It should be noted, however, that other implementations, such as a side-looking endoscope, also fall within the scope of the present invention.
• lens arrangement 22 includes a cylindrical graded-index ("GRIN") lens.
• GRIN cylindrical graded-index
• a miniature compound lens assembly made from injection molded polymer components typically polycarbonate
• lens arrangement 22 is preferably cylindrical with a total height of no more than about 1.5 millimeter and a diameter of no more than about one millimeter.
• the field of view of lens arrangement 22 is preferably at least about 60°, and most preferably at least about 90°.
• Image sensor chip 18 is preferably a CMOS chip with major dimensions of roughly one millimeter square. Roughly half of the surface area (e.g., a square of side roughly 0.7 mm) accommodates the sensor array 20 while the remaining surface is used for the associated electronic components for reading the array, shown schematically in Figure 9, as is known in the art. Thus, the area of two-dimensional array 20 is typically no more than about half a square millimeter (i.e., 5xlO "7 m 2 ). It has been found that these dimensions, with current production technology commercially available, are sufficient for implementing a monochrome sensor array of resolution approximately 100x 100 pixels.
• Each pixel is structured from the classical three-transistor architecture as described in Figure 10.
• Switch Ml is effective to reset the pixel and to charge the photodiode. Impinging light then discharges the diode and creates a voltage difference compared to the reset level.
• the photodiode voltage is read out via transistor M2 that acts as a source follower. The output voltage is fed into the column readout.
• the sensor operates in a 'rolling shutter 1 mode, i.e., each row in turn is reset during reading of that row.
• the rest of the components of image sensor chip 18 illustrated in Figure 9 are the necessary peripheral logic to read out the array.
• the control logic includes a vertical address decoder, horizontal shift register, column amplifiers to remove fixed pattern noise and a section generating the required frame and line pulses controlled by an on-chip oscillator. Since the area of the chip is extremely small, it is not possible to incorporate more sophisticated features such as programmable gain, offset adjustment, internal automatic gain control etc. on the chip. Instead, the more sophisticated control is preferably implemented by use of a separate controller located remote from the sensor and connected by wires passing along the endoscope. This subdivision requires bi-directional communication between the controller and the imaging arrangement, as will be discussed further below.
• light from a point source is radiant on a surface in front of the source with a flux density that varies inversely as the square of the distance between the source and the surface. For instance, the difference between the flux density radiated on two surfaces, one located 1 mm from the source and the other 20 mm from the source, is a factor of 400.
• the dynamic rage of the image sensors is finite. Often, when an image combines areas of very high brightness and very low brightness, the result is either saturation of the brighter areas or poor display of the darker areas.
• the image combines very close and very far portions of tissue, from adjacent tissue at the side to 25-30 mm along the center of the tube. Consequently there is very big difference between the light reflected from the adjacent tissue and the far portions.
• An image of such tube necessarily suffers from either saturation of the very proximal tissue or too poor noisy quality of display of the dark areas at the center of that tube.
• each video frame is preferably exposed with two different exposure durations.
• Figure 7 shows the output response of two such exposures.
• T 1 For a scene containing a wide range of brightness levels, a sufficiently short exposure duration T 1 avoids saturation over the entire scene.
• the present invention preferably employs a plurality of light sources of different colors, and particularly, red, green and blue (RGB) sources, illustrated here as LEDs 24a, 24b and 24c.
• RGB red, green and blue
• Combining the double exposure technique with the three separate color illuminations yields six exposures for each color frame.
• Each exposure has its own duration, controlled externally by switching on and off the corresponding illumination source according to exposure control methods to be described below.
• the pairs of long/short exposures are first combined as described above,
• the final color image is then the combination of the double exposures for each of the three RGB exposures.
• each of the three basic RGB layers is collected according to the double exposures technique described above.
• the final color image is achieved by chromatic correction done by multiplication of each color layer in the white balance constants. Exact synchronization is needed to switch the LEDs on and off to get homogenous exposure over the entire frame each of the entire frame and to avoid mixing of colors between frames.
• a rolling-shutter read cycle is preferably triggered between exposures, i.e., when the scene is dark due to lack of illumination, to avoid mixing of the color frames.
• any image sensor suffers to some extent from fixed pattern noise that arises from the variation of the offset and gain of the individual pixels.
• Data to correct these variations can be measured and stored in a memory, for example an EPROM, implemented as part of the endoscope. Additional distortion may result from any uncorrected chromatic aberrations from lens arrangement 22. Since every color has its own layer, geometric distortions due to color shifts can be corrected mathematically using geometric transformations. The constants for these transformations can be calibrated individually and stored in the memory of the endoscope.
• image sensor chip 18 is rectangular, and more particularly square.
• Light sources 24 ⁇ , 24b and 24c are deployed along no more than two edges of rectangular chip 18, and sensor array 20 is located proximal to a corner of image sensor chip 18 furthest from the aforementioned two edges.
• imaging arrangement 16 preferably further includes a quantity of a substantially opaque medium 28 deployed at least between light sources 24 ⁇ , 246 and 24c and sensor array 20 in such a manner as to avoid obscuring propagation of illumination from the light source towards the scene.
• imaging arrangement 16 preferably also includes an optically dispersive medium 30 distally overlying light sources 24 ⁇ , 24b and 24c such that optically dispersive medium 30 is effective to disperse illumination from the light sources 24 ⁇ , 24Z» and 24c, thereby illuminating the scene viewed from the distal tip portion, without obscuring light reflected from the scene from reaching lens arrangement 22.
• This may advantageously be achieved by ensuring that lens arrangement 22 extends distally beyond light sources 24 ⁇ , 24b and 24c, and deploying optically dispersive medium 30 surrounding lens arrangement 30 without overlying the lens.
• Suitable optically dispersive media include, but are not limited to, adhesives described commercially as "fogged epoxy” and clear adhesives with admixtures of small crystalline or otherwise particulate solids which cause suitable scattering of light.
• imaging arrangement 16 may further include a substantially transparent medium (not shown) overlying both optically dispersive medium 30 and lens arrangement 22 to encapsulate and protect imaging arrangement 16.
• imaging arrangement 16 includes a common circuit board 32 which provides a common mounting structure for light sources 24a, 24b and 24c and image sensor chip 18.
• the light sources may be raised above the surface level of the circuit board by use of a support block not shown) in order to reduce or avoid casting of an illumination shadow by the lens assembly.
• Circuit board 32 preferably fits within a circular cross-section of diameter 2 millimeters. Most preferably, a roughly circular circuit board of diameter no more than about 1.8 millimeters is used. This facilitates construction of an endoscope with an external diameter no greater than about 2 millimeters.
• Electrical wires 42 for supplying power to light sources 24 ⁇ , 246 and 24c and for power supply and data transfer to and from image sensor chip 18 pass along elongated flexible body 12.
• connections of the wires are preferably achieved via connection to contact regions of the circuit board on a proximal side of the circuit board, i.e., facing away from the viewing direction. Connections between these contact regions and the components on the circuit board are achieved via through-bores in the circuit board, as is known in the art. Alignment of the wires for attachment to the corresponding contact pads may be achieved using various techniques.
• the wires are held in the required formation by a positioning disc 34 configured to leave a small unclad length of each wire projecting.
• An adapter block 36 is formed with peripheral channels within which the ends of the wires are attached with a small drop of conductive adhesive or solder.
• the peripheral channels are formed with conductive coatings which are electrically connected to contact pads 38.
• Contact pads 38 are deployed so as to align with corresponding contact regions on the rear face of circuit board 32.
• Adapter block 36 and circuit board 32 are typically connected with a drop conductive adhesive or solder applied to each of contact pads 38.
• distal tip portion 14 includes a position sensor arrangement 40 ( Figure 2), including a plurality of sensor coils, deployed near a proximal side of the circuit board.
• Position sensor arrangement 40 is preferably implemented as a sensor arrangement of a six-degrees-of-freedom position measurement system, and most preferably according to the teachings of U.S. Patent No. 6,188,355 and published PCT Application Nos. WO 00/10456 and WO 01/67035, all of which are hereby incorporated by reference.
• the position sensor arrangement 40 provides tracking of the position of imaging arrangement 16 within the body, thereby facilitating navigation of the endoscope and integration of the imaging data with other available sources of information.
• image sensor chip 18 is connected to exactly four wires. Operation of imaging arrangement 16 is controlled by a controller, which may be implemented as a dedicated electronics unit or as part of a general purpose computer system 44 ( Figure 1), associated with a proximal part of elongated flexible body 12. In order to achieve four-wire connection of the image sensor chip, the controller is electrically associated with image sensor chip 18 via no more than two communication wires 42 extending along the elongated flexible body 12.
• Communication is preferably achieved bi-directionally, by configuring image sensor chip 18 to be responsive to a frame request signal generated by the controller to perform a read cycle of the two-dimensional array of light-sensitive pixels in a rolling- shutter mode, and to transmit a single frame of image data to the controller.
• Both the frame request signal and the image data are transmitted via one or both of the two communication wires.
• at least the image data is transmitted on both wires using a differential signal in order to minimize data corruption.
• Synchronization of the read cycle of image sensor chip 18 is preferably controlled by the controller.
• image sensor chip 18 is preferably configured to wait after transmitting the single frame of image data until receiving a subsequent frame request signal from the controller.
• exposure control is preferably primarily achieved by controlling the activation time of the illumination sources, also controlled by the controller. However, for efficient use of time, it is preferable that a read cycle of the chip is initiated immediately after each exposure is completed.
• the controller is preferably configured to generate frame request signals at the end of pairs of unequal periods, corresponding to the aforementioned short and long exposure times for each color illumination. As explained earlier, pairs of similar frames with different exposure durations are generated, and are co-processed by the controller to derive an enhanced frame having a dynamic range greater than each of the pair of similar frames.
• the controller is preferably also configured to combine the enhanced frames for each of the three colors of illumination to generate a color image.
• FIG. 11 One non-limiting example of a simple electronic implementation for the bidirectional communication between image sensor chip 18 and the controller is illustrated in Figure 11.
• the electronics of image sensor chip 18 is here designated 500 while the external electronics (part of the controller) is designated 550.
• the image sensor chip operates in rolling shutter mode with external synchronization via a frame request from the controller transmitted along the video output line 510, which is preferably a dual differential line.
• the video out signal is derived by driver 506 and transmitted through the closed switch 504 and along line 510 to a receiver 552, which delivers the video signal 556 to its final destination (e.g., computer system 44 or any other required equipment).
• a receiver 552 which delivers the video signal 556 to its final destination (e.g., computer system 44 or any other required equipment).
• switch 504 is opened, and the image sensor waits for a frame request command. In this state, the cells collect photon electrons.
• switch 554 is closed, grounding line 510, and thereby changing the output of amplifier 502 so as to activate the next read cycle of the image array.
• the read cycle also resets the pixels during the image output data transfer, row by row.
• the external electronics 550 can be controlled by a PC, micro-controller or any other suitable state machine.
• FIG. 12 A second non-limiting example of a more sophisticated architecture is described in figure 12.
• the image sensor electronics 600 and external electronics 650 are connected via a bi-directional communication line 610, again preferably a dual differential line.
• a first switch 602 connects the output driver 604 to line 610 and a second switch 652 connects line 610 to an amplifier 654 to receive the signal.
• switches 602 and 652 change state, allowing driver 656 to send digital data to the image sensor, received by amplifier 606 and stored into memory 608.
• This digital data is used to control the delay between sequential video frames using count down counter.
• this port can serve also for other control commands.
• Apparatus 200 useful for assembly of imaging arrangement 16, and in particular, for correctly aligned attachment of lens arrangement 22 by clear adhesive to the sensor array of chip 18.
• Apparatus 200 has a first adjustable platform 202 with a clamping surface 204 ( Figure 6B) for gripping circuit board 32 which carries image sensor chip 18.
• Adjustable platform 202 is mounted beneath a microscope 206 so that chip 18 can be viewed and so that the sensor array 20 can be centered under a reticule of microscope 206 by adjustment of platform 202.
• Apparatus 200 further includes an adjustable support 208 to which a hinged flap 210 is hingedly mounted.
• Hinged flap 210 includes a lens holder 212 for clamping lens arrangement 22 in a well-defined centered position. Adjustable support 208 also allows adjustment of the position of hinged flap 210 for centering a marker on the rear (upper) side of lens holder 212 relative to the microscope reticule when the flap is in its lowered position ( Figure 6C). Before use, hinged flap 210 is lowered to the position of Figure 6C and adjustable support 208 is adjusted until lens holder 212 is centered relative to the microscope reticule. Flap 210 is then raised to the position of Figure 6A 5 and lens arrangement 22 is inserted into lens holder 212.
• Circuit board 32 is clamped to clamping surface 204 and adjustable platform 202 is adjusted to center the sensor array 20 relative to the microscope reticule.
• a small quantity of clear adhesive is then applied to the end of lens arrangement 22 and hinged flap 210 is gently lowered to bring lens arrangement 22 into contact with the sensor array where it is left until dry.
• Hinged flap 210 is preferably configured to apply a predefined contact pressure between the lens arrangement and the sensor array, thereby helping to ensure that the lens arrangement seats itself squarely against the chip surface.

Applications Claiming Priority (2)

Publications (3)

Family

ID=36740897

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (55)

Citations (4)

Family Cites Families (15)

• 2006
  • 2006-01-26 ES ES06701745.9T patent/ES2528722T3/es active Active
  • 2006-01-26 US US10/571,695 patent/US20080255416A1/en not_active Abandoned
  • 2006-01-26 AU AU2006209044A patent/AU2006209044A1/en not_active Abandoned
  • 2006-01-26 EP EP06701745.9A patent/EP1845835B1/de not_active Not-in-force
  • 2006-01-26 WO PCT/IL2006/000113 patent/WO2006080015A2/en active Application Filing
  • 2006-01-26 JP JP2007552806A patent/JP2008532574A/ja active Pending

Patent Citations (4)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events